use std::collections::HashSet;

struct Solution {}

fn main() {}

impl Solution {
    pub fn find_disappeared_numbers(nums: Vec<i32>) -> Vec<i32> {
        let mut nums_set = nums.clone().into_iter().collect::<HashSet<i32>>();
        let mut res_vec = Vec::new();
        for num in 1..(nums.len() as i32) + 1 {
            if nums_set.contains(&num) {
                continue;
            }
            res_vec.push(num);
        }
        res_vec
    }
}
